Sheet metal sickle guard forming process



May 26, 1959 N. R. KRAUsE ET AL 2,887,761

SHEET METAL SICKLE GUARD FORMING PRCCESS GriginaflFiled June 16. 1951 2 Sheelts-Sheet 1 May 26, 1959 N. R. KRAUsE ET AL 2,887,761

SHEET METAL sIcKLE GUARD Ecm/:ING PROCESS Original Filed June 16. 1951 2 Sheets-Sheet 2 United States Patent SHEET METAL s-ICKLE GUARD FoRNnNG PROCESS Continuationy of abandoned application Serial No. 231,982, June 16, 1951. This application November 26, 1954, Serial No. 471,264

2 Claims. (Cl. 29-148.3)

The present invention relates broadly to the metal working art and more specifically to a process for forming and shaping sheet metal into a sickle guard.

It is, therefore, a primary object of the present invention to provide a method of forming and shaping sheet meta1 into sickle guards which entails relatively few operations, which can be eected on a high production basis, and which is comparatively economical.

Another object of the present invention is to provide a method of manufacturing a sheet metal guard, which guard possesses superior strength and resiliency with respect to cast or forged guards of the type presently being used.

A further object of the present invention is to provide a method of forming and shaping a single piece of relatively light-weight metal into a sickle guard, the resulting sickle guard being characterized rby its pleasing appearance, its resistance lto impact and bending stresses, its relatively lightweight, and its small cost.

Further objects and advantages of the invention will `be apparent from the following description and drawings wherein:

Fig. 1 is a plan view of a sickle bar construction embodying the present invention, with parts broken away.

Fig. 2 is a front view of the sickle bar construction shown in Fig. 1, with parts broken away.

Fig. 3 is a sectional view taken on the lfine 3 3 of Fig. l. Fig. 4 is a sectional View taken on the line 4 4 of Fig. 1.

Fig. 5 is a plan view of a sheet metal :blank which is to be formed into a sickle guard.

Fig. 6 is a right-rear elevational view of the blank after the first forming operation.

Fig. 7 is a right-rear elevational View of the structure Vshown in Fig. 6 afterthe nal forming operation.

This application is a continuation of application S.N. 231,982, filed June 16, 1951, now abandoned, the sickle bar construction disclosed but not claimed herein being claimed in an application tiled on even date herewith.

Referring to the drawings, a sickle bar construction embodying a sickle guard manufactured in accordance with the teachings of the present invention comprises a guard bar 14 adapted to be secured to a traveling framework, a portion of which is shown at 15, such as that in a harvester of any conventional or suitable construction. Secured to and protruding forwardly from the guard bar 14 are a plurality of 'gangs 16 which comprise sickle guards 17, ledger plates 18, and a stabilizing plate 19. A sickle section 20 is provided for cooperating with the cutting edges of `the ledger plates as will appear hereinafter.

The guard bar 14 is a continuous angle bar extending forwardly at its upper surface as at 20a. Bolt accommodating holes 21 are formed equidistant from one another along the portion 20a for reception of carriage bolts or other suitable fastening means 22 for fastening the gangs 16 to the guard bar 14.

In the manufacture of the pressed guards in accord-f ance with the teachings of the present invention-'an arrow-shaped configuration or blank 23 is stampedby means of a suitable stamping or other type machine from sheet metal, preferably steel,v see Fig. 5. This blank is formed with a head portion 24 having rearwardly diverging Wings or canopies 25, rearwardly diverging straight edge portions 26 having lateral extensions 27 adjacent the rearward ends thereof, and forwardly extending slots 28 which form the juncture of the straight edge portions 26 Iwith the diverging Vwings 25. The blank is placed in an automatic pressing or other suitable machine and acted upon by a suitable die which bends the rblank along the lines 29-29 and 30--30 so that the blank-laterally of the lines 29--29 and'30-130 extends upwardly'finsa substantially vertical direction so as to form sides which are substantially symmetrical as to size andshape, see

Fig. 6. Simultaneously the die presses that portionof the blank adjacent its rear end and `between lines 29-29 and 30--30 sufficiently downwardly to forni a seating portion 30a which is substantially parallel to the upper surface of the straight edge portions 26. The vhead portion 24 and the wings 25 are then acted upon by another die which presses the head portion and the wings inwardly so that they join along the medial plane of the guard, see Fig. 7. The wings and head portion are then secured together along their line of juncture by means of welding or any other suitable mechanical means and an opening 31 is punched or drilled medially in the seating portion 30a for accommodating the fbolts 22 as will'4 be more fully explained hereinafter. It will be appreciated that the above method of manufacture entails .relatively few steps and produces a pressed steel guard which is a finished product as far as additional machining is coucerned, the lateral surface of the straight edge portions 26 being substantially co-planar and. serving vas. ledger plate supporting shoulders 32. It will also be :appreciated that the substantially trough-like forwardly converging shape of the guard possesses great strengthv while being capable of being manufactured in 'great numbers inza relatively short time. 1

The ledger plates 18 are shaped so as to fit snugly o the ledger plate supporting shoulders 32 and areformed with a forwardly extending lip 33 adjacent the-forward end thereof and a shaped portion 34 adjacent ythe rearward en-d thereof. The ledger plates are fixed forwardly upon the shoulders 32 by wedging the lip 33 between the inner surfaces of the head portion 24 forwardly of the slots 28, and the lip 33 is so portioned as to have a tight t when forced therein for preventing lateral deflection of the ledger plate due to the reciprocating action of the sickle section 20. The shaped portion 34 is so shaped as to fit lbetween the extensions 27 when the ledger plate is wedged forwardly into theguard, the'extensions 27 aiding in preventing dellection of the guard due to the reciprocating action of the sickle section. The upper surfaces of the extensions are substantially co-planar with the upper surface of the ledger plate when the ledger plate is positioned on the shoulders 32 for presenting a continuous surface for attachment to the guard bar 14 as will be appreciated more fully hereinafter. An opening 3S is formed adjacent thel rearward end of the ledger plates 18 for reception of the bolts 22 as will be explained shortly.

Each gang 16 has a stabilizing plate 19, which in the present instance is substantially angular-shaped in cross section and comprises a rearwardly extending portion 37 and an upwardly and forwardly extending portion 38. A plurality of saddles or cut-out portions 39 are formed in the portion 38 and are so positioned as to cradle or embrace the sides of the guards 17. The portion 37 seats against the seating portions 30a of guards 17 and hasformed therein a plurality of openings 40 for reception of the bolts 22, and a nut 41 is threaded on the respective end of each of the bolts 22 for drawing the stabilizing plate 19 and the respective guards 17 and ledger plates 18 against the undersurface of the portion 20a of guard bar 14, the stabilizing plate 19 maintaining the guards 17 in their proper position with respect to the guard bar. Each stabilizing plate 19 accommodates four guards in the present instance and a stabilizing plate together with its respective guards 17 and ledger plates 18 constitutes a gang 16. The stabilizing plate of one gang abuts the stabilizing plates of its adjacent gangs and the stabilizing plates are so proportioned that the guards 17 extend forwardly from the guard bar 14 in equally spaced substantially parallel relationship when the gangs are secured thereto. It will be appreciated that an individual gang 16 can be disassembled from the guard bar 14 withoutimpairing the operating efiiciency of the remaining gangs. This is accomplished by removing the nuts 41 from the proper bolts 22 and allowing the respective stabilizing plate 19, its guards 17 and ledger plates 18 to drop downward out of engagement with the respective bolts 22.

The sickle section 20 comprises a sickle bar 42 which has secured to the undersurface thereof a plurality of triangular sickle blades 43, the sickle blades 43 forming the sliding surface of the sickle section 20. The blades are secured to the undersurface of the bar 42 by means of rivets or other suitable fastening means 44 so that the sickle blades can be easily replaced by removing the necessary rivets. It will be appreciated that greater continuity of surface is achieved between the sickle blades 43 and the ledger plates 18 by reciprocating the entire undersurface of the blades upon the ledger plates, increasing thereby the cooperation between the respective cutting edges while decreasing the tendency of the sickle section to tilt upon the ledger plates. Also, the guard can be a simple straight member which does not need an offset, groove, or notch to clear bar 42 as would be necessary if the bar 42 were beneath the blades 43, as is common in prior construction.

A pressure clip 45, preferably formed of spring steel or other suitable material, is provided for each gang 16 for holding the sickle blades 43 in frictional engagement with the ledger plates 18 besides providing in cooperation with the forward surface of portion 20a of guard bar 14 a transverse guideway for sickle bar 42. Each clip 45 is secured rearwardly to the portion 15 of the traveling framework by means of a suitable bolt or the like 46 and extends forwardly between two adjacent guards 17. A downwardly extending portion 47 is formed adjacent the forward end of each clip 45 and a slightly elongated opening 47a is formed medially in the clip for reception of a hold-down bolt 48. The hold-down bolt 48 is threaded into a threaded opening 49 formed in the portion 20a of the guard bar 14 to move the portion 47 sufficiently close to the sickle blades 43 to maintain the sickle blades in frictional contact with the ledger plates 18. The hold-down bolt 48 is of a length sutiicient to extend through an opening 50 formed in the stabilizing plate 19 when the portion 48 is at its desired position and a lock nut 51 is threaded on the end thereof for locking the bolt 48 against unintended turning in the threaded opening 49. If the operator wishes to adjust the pressure exerted by the clip 45 against the sickle blades 43, he must rst loosen nut 51 sufficiently to allow hold-down bolt 48 to be threaded into or out of threaded opening 49. When the proper adjustmentl for clip 45 is reached, lock nut 51 is again drawn against the stabilizing plate 19, locking thereby the hold-down nut against turning in the threaded opening 49. The bolt 46 is accommodated in a slot 51a formed in the pressure clip 45 and opening 47a is formed sufficiently large to provide for backward or forward adjustment of the pressure clip for adjusting the clearance of the sickle bar between the guard bar and the clip.

Having thus described our invention, it will be appreciated that the method of forming and shaping sheet metal into sickle guards entails relatively few operations and that the resulting sickle guards are highly resistant to impact and bending stresses, are relatively light weight, and can be manufactured quickly and at small cost.

What is claimed is:

l. A method of forming a sickle guard from sheet metal which comprises stamping a blank having a head portion with rearwardly diverging wings defining straight sides and a body portion having rearwardly diverging straight edge portions, forcing a longitudinally disposed wedge shaped portion in the center of the blank downwardly to form a rearwardly open forwardly converging channel formation substantially U-shaped in cross section and having substantially symmetrical sides, pressing the wedge shaped portion adjacent the large end thereof to form a seating surface displaced from the surface of the channel, bending the sides of the head portion and wings inwardly into contact with each other along a line substantially medial of the channel formation so as to form a sickle guard with a pointed end and a canopy extending over the body portion but terminating short of said seating surface, welding these sides together, and then forming a hole in the seating surface.

2. A method of forming a sickle guard from sheet metal which comprises stamping a blank having a head portion with rearwardly diverging wings defining straight sides and a body portion having rearwardly diverging straight edge portions, lateral extensions adjacent the rearward end of the edge portions, and longitudinally extending slots which form the juncture of the edge portions and the wings, forcing a longitudinally disposed wedge shaped portion in the center of the blank downwardly to form a rearwardly open forwardly converging channel formation substantially U-shaped in cross section and having substantially symmetrical sides, pressing the wedge shaped portion adjacent the large end thereof to form a seating surface displaced from the surface of the channel, bending the straight sides of the head portion and wings inwardly into contact with 1each other along a line substantially medial of the channel formation so as to form a sickle guard with a pointed end and a canopy extending over the body portion but terminating short of said seating surface, welding these straight sides together, and then forming a hole in the seating surface.

References Cited in the file of this patent UNITED STATES PATENTS 18,340 Howou oor, 6, 1857 105,311 Crosby July 12, 1870 2,278,393 vutz Mar. 31, 1942 2,431,509 Ronfoldt Nov. 25, 1947 2,431,663 Scranton Nov. 25, 1947 

